In honor of their sister and daughter, Mary Katherine, the six Conroy children and their parents, Maribeth and Jim, will hold their fifth annual Mary’s Christmas Party from 1 to 5 p.m. Sunday, Dec. 1, at the Marshfield Elks Lodge. The family will continue its tradition of collecting stocking stuffers to be donated to the children fighting cancer at Massachusetts General Hospital in Boston, where Mary Katherine received treatment.